For what it’s worth, the road to conducting at Oberlin is something that must be started in the student’s first year or it is too late. Whether a student is able to start in the first year is pretty much up to the conducting faculty.
My D is a jr VP at Oberlin. PM me if you have questions about Oberlin.
Considering your family is from Texas, I would also consider Rice University. The voice department at the Shepherd School of Music is one of the best in the country.
Also, another note, I would hesitate to call your son a “true basso profondo”, especially to potential voice professors. While I’ve never heard your son sing, the basso profondo fach is usually a title reserved for older men, as the voice and the low notes develop much further down the road. And voices will change dramatically, especially at the collegiate level. It’s usually a fach, and it’s corresponding group of repertoire, that is decided much later in one’s career. I know a lot of college professors (especially those at the upper-level conservatories) can tend to be a little bit snooty when someone comes in to audition saying they are a “dramatic soprano” or a “full-lyric tenor”, for example, and then sing that repertoire at age 18. 
Certainly consider Rice, but realize the undergraduate VP program there is extremely small, and the department is mostly focussed on grad students. It is an excellent program, but not for everyone.
Rice would seem out of range academically based on the OP description of grades and test scores.
My D is an undergrad VP major at The Shepherd School of music at Rice. As at 18 year old soprano being in an extremely small, extremely selective BM program is where she wants to and needs to be. Her voice teacher has much time to focus on her, she’s learning from the MM’s in her studio & most importantly her instrument is being protected and nourished. Something many undergrad programs cannot do.
@songbirdmama is correct. Its not for everyone. it’s probably not a program for someone out of HS who desires to be performing constantly. It’s for the real deal, for the long haul.